Constantly getting logged out of apps on iOS 10.1.1
I'm on an iphone 7 plus on iOS 10.1.1 and recently I've experienced being constantly logged out of apps, such as facebook, slack, npr one, instagram, facebook, etc. There doesn't seem to be any particular thing that makes the apps log me out. I can switch between apps ok for a while then I'll switch back to an app and I'll be logged out again. Any ideas?
iPhone 7 Plus, iOS 10.1.1